1. Field of the Invention
The invention relates to improving the antiwear and load carrying properties of a lubricant. More particularly, it is concerned with improving such properties by adding to the lubricant a small amount of a phosphorus-containing compound.
2. Description of the Prior Art
Lubricants are subject to heavy stresses that can affect their antiwear and load carrying ability. Thus, there has been considerable effort to discover classes of compounds that will aid in retaining or, preferably, in improving these important properties.
For example, sulfur compounds have been used for the purpose, as is taught in U.S. Pat. No. 3,697,499. Unfortunately, the presence of sulfur in lubricants may cause severe metal corrosion, especially copper. To overcome this, special processes have been used to moderate the effect of sulfur as in U.S. Pat. No. 3,697,499, or other materials have been used, among them certain phosphorus compounds as lubricant additives. U.S. Pat. No. 3,663,439, for instance, discloses lubricating oils where extreme pressure properties have been improved by adding thereto a reaction product involving a trihydrocarbyl phosphite.